2. Definition
Viscosity refers to resistance to flow or
stickiness, from a latin word “viscum alba”
Hyperviscosity syndromes (HVS) refers to
clinical sequelae of increased blood viscosity
3. CAUSES
Elevated blood, plasma or serum viscosity occurs in number of hematological
conditions such as;
INCREASED IMMUNOGLOBULINS:
multiple myeloma
waldenstrom macroglobulinemia
connective tissue disease
INCREASED BLOOD CELLS: hyperproliferative states such as;
leukemias
polycythemias
thrombocytosis
myloproliferative disorders
REDUCED DEFORMABILITY OF RBCs:
spherocytosis
sickle cell disease
RHEUMATOID HVS is rare but can occur due to aggregates of RF or intermediate IgG
complexes
4. PATHOPHYSIOLOGY
As serum proteins or cellular components increases, the blood become
more viscous. It leads to vascular stasis and tissue hypoperfusion then
lead to signs and symptoms of HVS syndromes.
confusion and mental status changes results from the increased viscosity
of the blood and decreased cerebral blood flow.
This sludging leads to segmental dilatation of retinal veins and retinal
hemorrhages.
mucosal bleed may occur from prolonged bleeding time caused by
myeloma proteins interfering with platelets functions.
cardiopulmonary symptoms also result from sludging of blood and
decreased microvascular circulation.
5. SIGNS AND SYMPTOMS
The triad of mucosal bleeding, visual disturbances and
neurological symptoms.
Tendency to bleed; most common manifestation. Gum
bleeding, epistaxis, PR bleed, menorrhagia and persistant
bleeding from minor procedures.
Cardiopulmonary symptoms: such as SOB, hypotension,
respiratory failure
visual changes ranging from blurring to vision loss
Neurological menifestations such as: vertigo, tinnitus,
hearing loss, paresthesias, ataxia, headaches, seizures,
somnolence progressing to stupor and coma.
6. Dermatological manifestations such as Raynaud
phenomenon, palpable purpura, digital infarcts, peripheral
gangrene
renal manifestations such as hematuria, sterile pyuria,
nephrotic or nephritic syndromes
Constitutional symptoms such as fatigue, weakness,
anorexia
7.
8. The clinician should have a high level of suspicion
for hyperviscosity syndromes in patients with
unexplained coma, altered mental status or
unexplained shortness of breath especially, in
patients with an underlying hematologic disorders.
9. PHYSICAL FINDINGS
Bruises on the skin
Facial flushing
Blood blisters in the mouth or back af the eye.
Decrease GCS, ataxia, nystagmus
Signs of CHF
Splenomegaly, palpable lymph nodes
Opthalmic examination may reveal:
decreased visual acuity
dilated retinal veins
sausage-linked or boxer segmentation of retinal veins
retinal hemorrhages
11. DIAGNOSIS
History and clinical examination:
any patient presented with unexplained coma/ altered
sensorium, SOB, and visual changes.
any patient present with classical triad of mucosal bleed,
visual changes and neurological manifestations and especially
those with underlying blood disorders.
Lab investigations
imaging studies
12. Lab clues:
CBC: erythrocytosis, leukemias, thrombocytosis, normocytic
normochromic anemia
Globulin gap more than 4
Metabolic panel: deranged RFTs, hypercalcemia,
pseudohyponatremia
Urine analysis: proteinuria, sterile pyuria, BENCE JONES
PROTEINS.
Protein electrophoresis
coagulation profile
Important markers such as LDH, VIT B12, B2 microglobulins,
ALP, uric acid
13. Imaging studies
Bone scan
CXR
Ultrasound abdomen and pelvis
CT & MRI brain
Echocardiography
14. DIAGNOSIS
The diagnosis of HVS is confirmed by measurement of
elevated serum viscosity in patients with characteristic clinical
manifestations of HVS. But there are no exact cut-off exists for
serum viscosity.
Normal serum viscosity: 1.4-1.8 units centipoises
Symptoms usually not seen at viscosities less than 4.
HVS usually manifests when viscosity is more than 5 units.
15. Measuring viscosity
Classically measured in one of 2 ways;
1: by determining rate of fluid flow as a result of applying a predefined
force
2: by measuring the amount of force required to achieve a predefined rate
of fluid flow.
Approximately 75% of labs use a “capillary tube” also known as
“Ostwald tube” viscometer to measure viscosity.
16.
17. Treatment
Hydration therapy
early apheresis such as plasmapheresis , leukaphresis,
platletphresis
phlebotomy
Standard therapies for bleeding, CHF
be caution with blood transfusions even when needed
Diuretics may even worse the condition
18. Plasmapheresis
Treatment of choice in most cases for initial management
and stabilization
plasmapheresis demonstrated to reverse the retinopathy and
other manifestations of HVS in most patients
As bleeding is a most common manifestation, urgent
plasmapheresis using a cell separator should be used to
reduced the likelihood of blindness from retinal hemorrhage/
retinal detachment.
Plasma exchange reduces the plasma viscosity by 20%-30%
per session
21. Prognosis
Definitive treatment of HVS depend upon the
underlying condition
If the underlying disorder kept untreated the HVS will
recur again
Prognosis of HVS depend upon underlying condition,
its severity and its response to treatment.